Hammer attachment for rotary drills



May 25, 1948. J. J. MOHR 2,442,140

AAMMER ATTACHMENT FOR ROTARY DRILLS Filed Nov. 15, 1944 INVENTOR. JOSEPH J. MOI/R BY FIG. 7 n/z/WI/fl AT TORNE Y Patented May 25, 1948 OFFICE HAMMER ATTACHMENT FOR ROTARY DBILLS Joseph J. Mohr, Encinitas, Calif. v Application November 13, 1944. Serial No. 563.13:

10 Claims. 1

My invention relates to a hammer attachment to be used in connection with conventional rotary drills or the like, more particularly used for riveting, chipping or like purposes, and the objects oi my invention are:

First, to provide a very eflicient hammer attachment which may be readily connected with conventional rotary drills or like revolving mechanism;

Second, to provide a power driven attachment for tools where there is a substantially constant delivery of force by the use of which rotary power drives the attachment to deliver a reciprocating movement;

Third, to provide an attachment of this class whereby hammer strokes to the operating tool are delivered in one direction only thus reducing shock to the operator;

Fourth, to provide an attachment of this class whereby arotary motion is converted to a reciprocating motion which motion is urged in one direction by resilient means and also permitting slight torque movement to prevent shock but providing relatively positive action;

Fifth, to provide an attachment of this class with provision for stopping the hammer when operating without the tool in place;

Sixth, to provide an apparatus of this class which is very simple and economical of construction, efiicient, durable and which will not readily deteriorate or get out of order.

With these and other objects in view as will appear hereinafter, my invention consists of certain novel features of construction, combination and arrangement of parts and portions as will be hereinafter described in detail and particularly set forth in the appended claims, reference being had to the accompanying drawings and to the characters of reference thereon which form a part of this application in which:

Figure 1 is a side elevational view of my attachment for rotary drills showing portions broken away to facilitate the illustration; Fig. 2 is a longitudinal sectional view taken from the line 22 of Fig. 1 and showing the hammer member in its down position and tool inserted and showing some of the parts in elevation to facilitate the illustration; Fig. 3 is a detailed side elevational view of the shank member 4; Fig. 4 is a detailed top or plan view of the adjustment member 2; Fig. 5 is a side elevational view of the cam member 5; Fig. 6 is a detailed side elevational view of the hammer cushion member H, and Fig. 7 is a fragmentary sectional view similar to Fig. 2 showing the hammer member in its up position.

Similar characters of reference refer to similar parts and portions throughout the several views of the drawings.

The casing member I, adjustment member 2,

2 adjustment nut 8, shank member 4, cam member 5, cam engaging roller 6, springs 1 and I, bearing cage 9, hammer member l0 and hammer stop member 'H, constitute the principal parts and ggirlilsions of my hammer attachment for rotary The casing member I is a single, hollow, circular in cross section member extending from end to end or the attachment. It is provided at its normally upper endwith an enlarged annular internally threaded portion la which is adapted to be screwthreaded onto the externally threaded end 01 a rotary drill casing and thus secured thereto. It is provided on opposite sides with slots I b and le which extend up into the enlarged portion la and a considerable distance below the same, as shown best in Fig. 2 of the drawings. The slot lb it will be noted extends upwardly into the enlarged portion some distance for permitting the assembling of the adjustment member 2 in position in the casing. This member 2 is shaped as shown best in Figs. 2 and 4 of the drawings, provided with a central opening 2a and with extended lug portions 2?; and 20 which are adapted to engage a thread 30 on the inner side of an adjustment nut 3, as shown best in Fig. 2 of the drawings. This adjustment nut 3 is revolubly mounted around the casing member I just below the enlarged portion Ia. This provides means for drawing the member 2 downwardly providing additional compression on the springs 1 and 8 for adjustment purposes. This adjustment nut 3 is provided with grooves 30 which are arranged to engage pin id in the casing member I, as shown best in Fig. 1 of the drawings.

Mounted centrally in the casing member I and disposed longitudinally therewith is the shank member 4 which is provided with an intemaliy threaded bore 6a which is adapted to be screw threaded on the rotary shank of the conventional rotary drill. This shank member ,4 is provided with a reduced portion to intermediate its ends and with an enlarged head 40 at its lower end. Mounted around this reduced portion 4b and above the head 40 is a ball bearing cage 9 in which are mounted spaced apart pairs of annular rows of ball bearings 9a, shown best in Fig. 2 of the drawings. This forms ball bearings for the cam member 5 which is revolubly mounted on the shank 4 and it is provided with a separate sleeve member 5a which fits around the shank member 4, as shown best in Fig. 2 and is provided with a shoulder 51: which rests on the cam member 5 and on this shoulder rests the compression spring 8 at one end and the other end engages the lower side of the adjustment member 2 and surrounding the shank member 4.

v This cam member is provided with an extended shoulder portion 5c upon which rests the lower shown in Fig. 2 of the drawings.

3 end of the spring I, the spring 1 being provided with an extended angular portion 1a which rests in a hole in the shoulder portion 50 which prevents the relative turning of the end portion Ia with the cam member 5. The upper end of the spring I is also provided with an extended angular portion lb whichflts in a notch in the member 2 to prevent relative torsional movement of the spring with the adjustment member 1,

The cam member is provided on its lower surface with a cam surface ill, with an abrupt portion 5e, as shown best in Fi 5 of the draw-" rality of pin or roller-bearings 6b, as shown best in Fig. 2 of the drawings. It will be noted that the bore 4d does not extend through the head portion of the shank member 4.

i This cam member 5 is provided with an externally screw threaded portion 5! on which is screw threaded the hammer member II) which extends downwardly to near the lower end of the enlarged bore portion of the casing l and is provided with a reduced extended hammer portion Illa at its lower end provided with a slot lllb arranged to receive a conforming lug on the end of the tool to be operated by said hammer at- Y tachment.

Positioned in the bottom of the larger bore of the casing I and positioned around the end Illa of the hammer member In is a hammer stop member II which is made of two duplicate members arranged to expand and contract and held together by means of a spring member Ila and held in position by means of a wire latch Ilb resting against a shoulder lie and fitted into a groove lid in the inner side of the casing I, as This member lib permits the expansion of the member II for receiving the end of the tool, but holds it down against the bottom end of the casing I. This hammer stop member ll serves as a stop for the hammer member II! when the tool is not in position and the shank in operation, thus reducing the vibration when the tool is not in position; it being noted that the stop member H, when in contracted position, as shown in Figure 7, supports the end portion Illa of the hammer member I!) maintaining the cam member 5 substantially out of the path of the cam engaging roller '6.

Inoperation the rotation of the shank 4 carrying the roller cam follower 6a engages the helical surface of the cam 5 and causes torsional deflection of the combined torsion and compression spring 1 building up a torsional load therein until the roller Ba reaches the precipice 5e at which time the precipice portion is quickly.

the spring 1.

Though I have shown and described a particular construction, combination and arrangement of parts and portions, 1 .do not wish to be bination and arrangement but desire to include in the scope of my invention the construction, combination and arrangement substantially as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a hammer attachment for rotary drills, the combination of a hollow casing, a shank member revolubly mounted centrally therein, an annular cam member provided with a cam surface on its lower edge surrounding said shank member, roller means in connection with said shank member engageable with said cam mem-' ber, a hammer in secured relation with said cam member and shiftable therewith, and a combined torsion and compression spring secured with said cam member at one end and said casing at its other end tending to hold said cam member in engagement with the cam engaging means on said shank member and also tending to hold said cam member against rotation.

2. In a hammer attachment for rotary drills, the combination of a hollow 'casing, a shank member revolubly mounted centrally therein, an annular cam member provided with a cam surface on its elower edge surrounding said shank member, roller means in connection with said shank member engageable with said cam member, a hammer in secured relation with said cam member and shiftable therewith, a combined torsion and compression spring secured with said cam member at one end and said casing at its other end tending to hold said cam member in engagement with the cam engaging means on said shank member and also tending to hold said cam member against rotation, and means for adjusting the tension of said spring.

3. In a hammer attachment for rotary drills,

o the combination of a hollow casing, a shank member revolubly mounted centrally therein, an annular cam member provided with a cam surface on its lower edge surrounding said shank member, roller means in connection with said shank member engageable with said cam member, a hammer in secured relation with said cam member and shiftable therewith, a combined torsion and compression spring secured with said cam member at one end and said casing at its other end tending to hold said cam member in engagement with the cam engaging means onsaid shank member and also tending to hold :sa'i'd cam member against rotation, means for adjusting the tension of said spring, and another spring positioned inside of said first mentioned spring arranged to engage said cam member.

4. In a hammer attachment for rotary drills, the combination of a hollow casing, a shank member revolubly mounted centrally therein, an annular cam member provided with a cam :surface on its lower edge surrounding said shank member, roller :means in connection with said shank member engageable with :said cam member, a Bha'mmerfin secured relation with said oam member :and shif table a combined torsion and compression spring secured with said cam member :at one and said Leasing at its other end tending to mold cam .member viin engagement with the cam engaging means on said shank member and also Jten'ding 'ito iholdsaid cam .mem'ber against rotation, an"other spring positioned inside of .said :firs't .mention'ed spring arranged to engage tsa'id eam member, :and an .adiustable member mounted .in :said "casing ex- ?limited to particular construction, com- =15 tending through the side walls ithereof to form a thread engaging member, and an adjustable nut revolubly mounted around said casing in threaded engagement with said adjustment member. 4

5. In a hammer attachment for rotary drills, the combination of a hollow casing, a shank revolubly mounted therein, a combined compression and torsion spring connected at its one end to said casing and surrounding said shank, a cam secured to the opposite end of said combined compression and torsion spring and having a cam surface outwardly of said shank, cam follower means on said shank engaging said cam surface, whereby torque of said cam imparted by said cam follower means is resisted by said combined compression and torsion spring, said cas-' ing having longitudinal slotted portions in the side walls thereof, an adjusting member connecting said combined compression and torsion spring to said casing and having projections extending through said slotted portions of said casing and an internally screw threaded sleeve engaging said projections of said adjusting member revolubly mounted externally of said casing for adjusting the compression of said combined compression and torsion spring.

6. In a hammer attachment for rotary drills, the combination of a hollow casing member arranged to be secured to a rotary drill casing, a shank member positioned centrally therein arranged to be secured to the shank of the rotary drill, a cam member provided with a cam surface on its lower edge surrounding said shank member, a hammer member secured thereto and reciprocally mounted in said casing, a roller member revolubly positioned in said shank mem. ber and extending therefrom and arranged to engage the cam surface of said cam member, and combined compression and torsion spring means surrounding said shank member and engaging said cam member and torsionally secured at one end to said casing member and at its other end to said cam member tending to hold said cam member in engagement with said roller and oppose torsional load on said cam exerted by said roller.

7. In a hammer attachment for rotary drills,

the combination of a hollow casing member arranged to be secured to a rotary drill casing, a shank member positioned centrally therein arranged to be secured to the shank of the rotary drill, a cam member provided with a cam surface on its lower edge surrounding said shank member, a hammer member secured thereto and reciprocally mounted in said casing. a roller member revolubly positioned in said shank member and extending therefrom and arranged to engage the cam surface of said cam member, and combined compression and torsion spring means surrounding said shank member and engaging said cam member and torsionally secured at one end to said casing member and at its other end to said cam member tending to hold said cam member in engagement with said roller, said spring means tending to hold said cam member also against rotation.

8. In a hammer attachment for rotary drills, the combination of a hollow casing member arranged to be secured to a rotary drill casing, a shank member positioned centrally therein arranged to be secured to the shank of the rotary drill, a cam member provided with a cam surface on its lower edge surrounding said shank member, a hammer member secured thereto and reciprocally mounted in said casing, a roller member revolubly positioned in said shank member and extending therefrom and arranged to engage the cam surface of said cam member, combined compression and torsion spring means surrounding said shank member and engaging said cam member and torsionally secured at one end to said casing member and at its other end to said cam member tending to hold said cam member in engagement with said roller, and against rotation, and means adjustable longitudinally with said casing for adjusting the compression of said spring means.

9. In a hammer attachment for rotary drills, the combination of a hollow casing member arranged to be secured to a rotary drill casing, a shank member positioned centrally therein arranged to be secured to the shank of the rotary drill, a cam member provided with a cam surface on its lower edge surrounding said shank member, a hammer member secured thereto and reciprocally mounted in said casing, a roller member revolubly positioned in said shank member and extending therefrom and arranged to engage the cam surface of said cam member, combined compression and torsion spring means surrounding said shank member and engaging said cam member and torsionally secured at one end to said casing member and at its other end to said cam member tending. to hold said cam member in engagement with said roller and against rotation, means adjustable longitudinally with said casing for adjusting the compression of said spring, and an expansible hammer stop member positioned in said casing in operative relation with said hammer member.

10. In a hammer attachment for rotary drills, the combination of a hollow casing member to be secured to a rotary drill casing, a shank member positioned centrally therein arranged to be secured to the shank of the rotary drill, a cam member provided with a cam surface on its lower edge surrounding said shank member, a hammer member secured thereto and reciprocally mounted in said casing, a roller member revolubly positioned in said shank member and extending therefrom and arranged to engage the cam surface of said cam member, combined compression REFERENCES CITED The following references are of record 'in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,006,339 Adams Oct. 17, 1911 1,052,823 Irvine Feb. 11, 1913 1,825,072 Keller Sept. 29, 1931 2,094,185 Norling Sept. 28, 1937 

